Tumor tissue from women with endometrial carcinoma is almost,never assayed for steroid hormone receptors although it is common knowledge that many of these cancers are progestinsensitive. Hormonal therapy if given, is nearly always administered on an empirical basis. Conventional biochemical estrogen (ER) and progesterone receptor (PgR) assays are difficult to perform and interpret in this malignancy since specimens often contain admixtures of benign, hyperplastic and neoplastic epithelium, stroma and myometrium, all of which may contribute receptor to a tumor cytosol. This study is designed to examine steroid hormone binding sites in tissue sections of endometrial carcinoma using fluorescein and rhodamine tagged conjugates of estrogen and progesterone (Fluoro-Ceps) which allow for localization of receptor at a cellular and subcellular level. Assay results will be correlated with those of immunocytochemistry using specific, monoclonal, antireceptor antibodies, and where possible, with biochemical ER and PgR assay values. All results will be correlated with a variety of clinical and pathological features, in particular with clinical endocrine response, disease-free interval and survival. The ultimate goal of the project is to identify the best possible assay that could be performed in a community hospital laboratory, which would aid clinicians in the selection of the most rational therapies for women with endometrial carcinoma.